Scroll compressor and scroll-type pressure transformer

ABSTRACT

A scroll compressor comprises a stationary scroll  122  fixed to a casing  121 , a stator  123  fixed to the casing  121 , bearing supports  126  and  127  fixed to the casing  121 , a rotary shaft  125  rotatably supported by the bearing supports  126  and  127  through bearings  128  and  129 , a rotor  124  fixed to the rotary shaft  125 , a hollow orbiting shaft  130  eccentrically and rotatably supported by the rotary shaft  125 , a mounting member  133  fixed within the hollow orbiting shaft  130 , an orbiting scroll  135  mounted to a mounting portion  134  of the mounting member  133 , a hollow orbiting plate  136  fixed to the lower portion of the hollow orbiting shaft  130 , an Oldham&#39;s ring  137  provided between the bearing support  127  and a hollow orbiting plate  136  and having protrusions  138  and  139 , grooves  140  and  141  formed on the bearing support  127  and the hollow orbiting plate  136 , the protrusions  138  and  139  being engaged with the grooves  140  and  141 , and a suction pipe  142  and a discharge pipe  143  connected to the stationary scroll  122.

FIELD OF THE INVENTION

[0001] The present invention relates to a scroll compressor used as air compressors, vacuum pumps, refrigerant gas compressors, and oxygen compressors. Further, the present invention relates to a scroll compressor used as a pressure transformer, namely, a scroll-type pressure transformer capable of compressing or reducing pressure of gas or air.

BACKGROUND OF THE INVENTION

[0002]FIG. 6 is a schematic sectional view showing a conventional scroll compressor as described in Japanese Patent Laid-Open Publication No. Sho 57-24486. Referring to FIG. 6, this compressor includes a bearing support 2 fixed to a casing 1, and a stationary scroll 3 fixed to the bearing support 2 and formed with a spiral lap. The compressor further includes a stator 4 fixed to the casing 1, a rotary shaft 6 supported rotatably by the bearing support 2 and the casing 1 through bearings 7 and 8, a rotor 5 fixed to the rotary shaft 6, and an orbiting shaft 9 supported orbitally by the rotary shaft 6 through bearings 10 and 11. Respective axes of the rotary shaft 6 and the orbiting shaft 9 are eccentrically arranged. The orbiting shaft 9 is provided integrally with an orbiting scroll 12 having a lap formed in the same configuration as that of the stationary scroll 3. These laps of the orbiting scroll 12 and the stationary scroll 3 are overlappedly engaged with each other to form a plurality of compression chambers. An Oldham's ring is provided between the orbiting scroll 12 and the bearing support 2 as an anti-self-rotation device 13 for preventing the self-rotation of the orbiting scroll 12. A suction pipe 14 is connected to the casing 1, and a discharge pipe 15 is connected to the stationary scroll 3.

[0003] In this scroll compressor, when a winding of the stator 4 is energized, the rotor 5 and the rotary shaft 6 are rotated and the orbiting shaft 9 are eccentrically orbited about the axis of the rotary shaft 6. However, the anti-self-rotation device 13 prevents the self-rotation of the orbiting shaft 9. Thus, the orbiting scroll 12 is orbited eccentrically to the stationary scroll 3 without any self-rotation of the orbiting scroll 12 and thereby the volume of the compression chambers formed between the orbiting scroll 12 and the stationary scroll 3 is gradually reduced. Then, a gas to be compressed, such as refrigerant gas, is sucked from the suction pipe 14, and introduced in the outboard side of the compression chambers through a vent hole (not shown) provided in the bearing support 2, whereafter the gas is compressed in the compression chambers, and discharged from the discharge pipe 15.

[0004] However, in such a scroll compressor, the anti-self-rotation device 13 is provided between the orbiting scroll 12 and the bearing support 2. Thus, the anti-self-rotation device 13 is increased in temperature with temperature raise of the orbiting scroll 12, resulting in shortened life of the anti-self-rotation device 13. Further, the thermal expansion of the anti-self-rotation device 13 leads to degraded efficiency of the scroll compressor.

[0005] In addition, such a scroll compressor has a problem to be improved in that it disadvantageously has a large dimension in the axial direction of the rotary shaft 6, i.e., in the longitudinal direction of the sheet of FIG. 6.

[0006] Further, there have been known scroll compressors using a mechanism wherein a scroll space between a stationary scroll and an orbiting scroll is gradually reduced by orbiting the orbiting scroll to the stationary scroll so as to compress the gas in the scroll space. Such scroll compressors are currently used for various purposes, such as a compressor for air conditioners, due to their advantages of high compression efficiency and excellent quietness. The above scroll compressors may serve as scroll vacuum pumps with a substantially same structure. These scroll vacuum pumps have the similar advantages as described above and thereby is used for various vacuum apparatuses.

[0007]FIGS. 16 and 17 show a conventional scroll compressor having such a structure. In this scroll compressor, when a rotary shaft 261 of a motor 260 is rotated, a crank 262 a of a crankshaft 262 coupled to the motor by a joint 263 is eccentrically moved. Then, an orbiting scroll member 280 rotatably attached to the crank 262 a is orbited without self-rotation by means of an anti-self-rotation mechanism 290. Thus, a scroll space between a scroll of the orbiting scroll member 280 and a scroll of stationary scroll members 270 a, 270 b are reduced in volume and thereby a gas introduced in the scroll space is compressed. The compressed gas is then discharged from a discharge port 278 through a discharge passage 271.

[0008] However, the above conventional scroll compressor has a complexified structure because the orbiting scroll member 280 is rotatably coupled to the crank 262 a of the crankshaft 262 through a bearing 283, and the self-rotation of the orbiting scroll member 280 is prevented by the anti-self-rotation mechanism 290 provided between the orbiting scroll member 280 and the stationary scroll member 270 b. Further, the bearing 283 of the orbiting scroll member 280 is required to have a high precision for bearing the crank 262 a and a high strength proof against the deforming force caused by the temperature difference in a partial portion of both scrolls. Furthermore, the basic circle diameter of the scroll is increased due to the orbiting mechanism with the bearing 283, and the dimension of the orbiting scroll member 280 is inevitably increased due to the structure with the anti-self-rotation mechanism. Thus, it has been difficult to promote downsizing for the structure of the conventional scroll compressors. Consequently, the conventional scroll compressors results in a undesirably increased cost. Further, due to the above particular structure of the anti-self-rotation mechanism 290, it is difficult to adequately lubricate, and the temperature of the anti-self-rotation mechanism 290 is increased with temperature rise of the orbiting scroll member 280. This leads to a degraded compression efficiency resulting from the deformation of the orbiting scroll member 280 caused by thermal expansion and vibration thereof, and to a shortened life of the anti-self-rotation mechanism 290.

[0009] Such a scroll compressor typically has a structure wherein a gas is compressed in a space formed by each scroll of the stationary scroll members 270 a and 270 b and the orbiting scroll member 280. Specifically, this scroll compressor comprises the motor 260, the crankshaft 262 coupled to the rotary shaft 261 of the motor through the joint 263, the pair of stationary scroll members 270 a and 270 b, the orbiting scroll member having a pair of scrolls on both sides thereof, the anti-self-rotation device 290, and an inlet port 276 and the discharge port 278 mounted to the stationary scroll members 270 a and 270 b. Spiral scrolls protrudes integrally from both sides of a disk-shaped base plate 285 of the orbiting scroll member 280, respectively. The volume of the space (scroll space) between the scrolls of the orbiting scroll member 280 and the spiral scrolls protruding integrally from respective inner surfaces of the stationary scroll members 270 a and 270 b are gradually reduced by the orbiting of the orbiting scroll member 280.

[0010] At the center of tthe orbiting scroll member 280 is provided with a cylindrical hub 281, and the crank 262 a of the crankshaft 262 penetrates the cylindrical hub 281 through the bearing 283. The innermost portion of the disk-shaped base plate 285 of the orbiting scroll member 280 facing the high-pressure areas of the scroll spaces is provided with a through hole 287 to communicate each high-pressure area of both scroll spaces. A discharge passage 271 is formed in the one stationary scroll member 270 b, and each high-pressure area in both scroll spaces communicates with the discharge port 278 through the discharge passage 271.

[0011] At the center of the stationary scroll member 270 a is provided with a through hole 273, and a rotary portion 262 b of the crankshaft 262 penetrates through the hole 273 through a bearing 274. Another through hole is also provided at the center of the stationary scroll member 270 b, and the rotary portion 262 b of the crankshaft 262 penetrates this through hole through a bearing.

[0012] The crank-type anti-self-rotation mechanism generally comprises a pair (two) of a rotatable crank between the orbiting scroll base plate and the casing. In this example, three rotatable cranks are provided in order to enhance the balance of the orbiting scroll base plate. Specifically, as shown in FIGS. 16 to 18, the anti-self-rotation mechanism 290 comprises three bearings 292, 292 and 292 provided in the base plate 285 of the orbiting scroll member 280, three bearings 294, 294 and 294 provided in the stationary scroll member 270 b, and a crank member 296 rotatably supported by the bearings 292 and 294 adjacent to each other. The three bearings 292, 292 and 292 provided in the orbiting scroll member 280 are located at apexes of a first equilateral triangle T1, respectively, and the three bearings 294, 294 and 294 provided at the stationary scroll member 270 b are located at apexes of a second equilateral triangle T2 slightly out of alignment to the first equilateral triangle T1 with the same size as the first equilateral triangle T1. The center O1 of the first equilateral triangle T1 lies at the center of the crank 262 a of the crankshaft 262. The center O2 of the second equilateral triangle T2 lies at the center of the rotary portion 262 b of the crankshaft 262. By virtue of this structure, the self-rotation of the orbiting scroll member 280 is prevented when the orbiting scroll member 280 is orbited with the radius r by the crankshaft 262.

[0013] The scroll compressor shown in FIGS. 16 to 18 may be used as a scroll vacuum pump. However, in either applications for the scroll compressor or the scroll vacuum pump, they inevitably involve the problems of complex structure, high cost, and degraded efficiency.

SUMMARY OF THE INVENTION

[0014] The present invention has been embodied to solve the above problem. Thus, it is an object of the present invention to provide a scroll compressor capable of achieving longer life of the anti-self-rotation device and maintaining stable efficiency.

[0015] It is another object of the present invention to provide a scroll compressor capable of reducing the dimension in the axial direction of the rotary shaft.

[0016] It is still another object of the present invention to provide a scroll-type pressure transformer capable of facilitating downsizing with a simple structure, and achieving an excellent pressure transforming efficiency.

[0017] According to one aspect of the present invention, there is provided a scroll compressor comprises a casing, a stationary scroll fixed to said casing, a stator fixed to said casing, a rotary shaft rotatably supported by said casing, a rotor fixed to said rotary shaft, an orbiting shaft eccentrically and rotatably supported by said rotary shaft, an orbiting scroll fixed to said orbiting shaft, and an anti-self-rotation device having a stationary portion fixed to said casing and a movable portion engaged with a certain portion of said orbiting shaft.

[0018] According to another aspect of the present invention, there is provided a scroll compressor comprising a fixed body, a stationary scroll which is a part of a compressor body and fixed to said fixed body, a rotary shaft rotatably supported by said fixed body, a driving device for rotatably driving said rotary shaft, a hollow orbiting shaft eccentrically and rotatably supported by said rotary shaft, an anti-self-rotation device for preventing the self-rotation of said hollow orbiting shaft, and a hollow orbiting scroll which is a part of said compressor body and fixed to said hollow orbiting shaft, wherein said compressor body is located inside said hollow orbiting shaft.

[0019] According to still another aspect of the present invention, there is provided a scroll compressor comprises a casing, a stationary scroll which is a part of a compressor body and fixed to said casing, a stator fixed to said casing, a rotary shaft rotatably supported by said casing, a rotor fixed to said rotary shaft, an orbiting shaft eccentrically and rotatably supported by said rotary shaft, an anti-self-rotation device for preventing the self-rotation of said orbiting shaft, and an orbiting scroll which is a part of said compressor body and fixed to said orbiting shaft, wherein said compressor body is located inside said rotor.

[0020] In this case, a hollow orbiting shaft may be applied as said orbiting shaft. Further, a mounting member may be fixed inside said hollow orbiting shaft to mount said orbiting scroll on said mounting member. Furthermore, said rotor may be fixed to said rotary shaft through a coupling member.

[0021] As a result of a attentive research considering the above problems, the inventors has discovered that the orbiting scroll member may be orbited without its self-rotation by mounting an orbiting shaft to a rotary shaft of a motor, and then attaching an anti-self-rotation mechanism to an orbiting shaft and mounting it between the orbiting plate and a casing, followed by fastening an orbiting scroll to the orbiting shaft. Based on this knowledge, the present invention has been completed.

[0022] According to further another aspect of the present invention, a scroll-type pressure transformer comprises a casing, a motor supported by said casing through a bearing and provided with a rotary shaft having an eccentric hollow portion, an orbiting shaft penetrating said hollow portion of said rotary shaft and rotatably supported by said rotary shaft through a bearing, an orbiting scroll member fastened to said orbiting shaft and having scrolls on both sides of said orbiting scroll member, a pair of stationary scroll members fixed to said casing and opposed to each scroll of said orbiting scroll member, an anti-self-rotation device provided in said orbiting shaft, a gas inlet port communicating with a low-pressure area of a pair of scroll spaces formed between said orbiting scroll member and said stationary scroll members on both sides of said orbiting scroll member, and a gas discharge port communicating with a high-pressure area of said scroll spaces.

[0023] Preferably, the orbiting scroll member is fastened to the orbiting shaft slidably in the axial direction under various operating conditions. It is also preferable that the anti-self-rotation device is provided between the orbiting plate fixed to the orbiting shaft and the casing. The scroll-type pressure transformer according to the present invention may serve as either of a scroll compressor and a scroll vacuum pump.

[0024] Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a schematic sectional view showing a scroll compressor according to the first embodiment of the present invention;

[0026]FIG. 2 is a sectional view taken along the line A-A of FIG. 1;

[0027]FIG. 3 is a schematic sectional view showing a scroll compressor according to the second embodiment of the present invention;

[0028]FIG. 4 is a schematic sectional view showing a scroll compressor according to the third embodiment of the present invention;

[0029]FIG. 5 is a sectional view taken along the line B-B of FIG. 4;

[0030]FIG. 6 is a schematic sectional view showing a conventional scroll compressor.

[0031]FIG. 7 is a schematic sectional view showing a scroll compressor according to the fourth embodiment of the present invention;

[0032]FIG. 8 is a sectional view taken along the line C-C of FIG. 7;

[0033]FIG. 9 is a schematic sectional view showing a scroll compressor according to the fifth embodiment of the present invention;

[0034]FIG. 10 is a schematic sectional view showing a scroll compressor according to the sixth embodiment of the present invention;

[0035]FIG. 11 is a sectional view taken along the line D-D of FIG. 10;

[0036]FIG. 12 is a sectional view showing an overall structure of one example of a scroll-type pressure transformer according to the present invention;

[0037]FIG. 13 is a partially exploded view of a part of the scroll-type pressure transformer of FIG. 12;

[0038]FIG. 14 is an exploded view of another portion of the scroll-type pressure transformer of FIG. 12;

[0039]FIG. 15 is a sectional view showing an overall structure of another example of a scroll-type pressure transformer according to the present invention wherein an orbiting scroll member is fastened to the orbiting shaft slidably in the axial direction;

[0040]FIG. 16 is a sectional view showing an overall structure of one example of a conventional scroll compressor;

[0041]FIG. 17 is a partially exploded view of the scroll compressor of FIG. 16; and

[0042]FIG. 18 is a schematic view showing a principle of an anti-self-rotation mechanism of the scroll compressor of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043]FIG. 1 is a schematic sectional view showing a scroll compressor according to the first embodiment of the present invention, and FIG. 2 is a sectional view taken along the line A-A of FIG. 1. As shown in these figures, a stationary scroll 22 is fixed to a casing 21, and a spiral lap is provided in the stationary scroll 22. A stator 23 is fixed to the casing 21. Bearing supports 26 and 27 are also fixed to the casing 21, and a rotary shaft 25 is rotatably supported by the bearing supports 26 and 27 through bearings 28 and 29. A rotor 24 is fixed to the rotary shaft 25. A motor comprises the stator 23 and the rotor 24. An orbiting shaft 30 is rotatably supported by the rotary shaft 25 through bearings 31 and 32, and respective axes of the rotary shaft 25 and the orbiting shaft 30 are eccentrically arranged each other. Thus, the orbiting shaft 30 is eccentrically and rotatably supported by the rotary shaft 25. An orbiting scroll 33 is mounted to the upper portion of the orbiting shaft 30. The orbiting scroll 33 is provided with a lap formed in the same configuration as that of the stationary scroll 22. These laps of the orbiting scroll 33 and the stationary scroll 22 are overlappedly engaged with each other to form a plurality of compression chambers. A compressor body comprises the stationary scroll 22 and the orbiting scroll 33. An orbiting plate 34 is fixed to the lower portion of the orbiting shaft 30, i.e., the downward section on the sheet of FIG. 1, and an Oldham's ring 35 having protrusions 36 and 37 is provided between the bearing support 27 and the orbiting plate 34. Grooves 38 and 39 orthogonal to each other are provided in the bearing support 27 and the orbiting plate 34, respectively, and the protrusions 36 and 37 are engaged with the grooves 38 and 39. This construction including the bearing support 27 and the Oldham's ring 35 provides an anti-self-rotation device which allows the orbiting shaft 30 to be eccentrically orbited and prevents the self-rotation of the orbiting shaft 30. Specifically, the support member 27 as the stationary portion of the anti-self-rotation device is fixed to the casing 21, and the Oldham's rings 35 as the movable portion of the anti-self-rotation device are engaged with the orbiting plate 34 as a certain portion of an orbiting shaft. Further, a suction pipe 40 is connected to the stationary scroll 22, and a discharge pipe 41 is connected to the stationary scroll 22. Each of the suction pipe 40 and the discharge pipe 41 communicates with the compression chambers. The eccentric-rotation driving unit comprises the casing 21, the motor, the rotary shaft 25, the orbiting shaft 30, and the anti-self-rotation device.

[0044] In this scroll compressor, when a winding of the stator 23 is energized, the rotor 24 and the rotary shaft 25 are rotated, and the orbiting shaft 30 is eccentrically orbited about the axis of the rotary shaft 25. However, the anti-self-rotation device including the Oldham's ring 35 prevents the self-rotation of the orbiting shaft 30. Thus, the orbiting shaft 30 and the orbiting scroll 33 are orbited eccentrically to the casing 21 and the stationary scroll 22 without any self-rotation of the orbiting shaft 30 and the orbiting scroll 33 and thereby the volume of the compression chambers formed between the orbiting scroll 33 and the stationary scroll 22 is gradually reduced. Then, a gas to be compressed, such as air, is sucked from the suction pipe 40, and compressed in the compression chambers, whereafter the gas is discharged from the discharge pipe 41.

[0045] In this scroll compressor, since the support member 27 as the stationary portion of the anti-self-rotation device is fixed to the casing 21, and the Oldham's rings 35 as the movable portion of the anti-self-rotation device are engaged with the orbiting plate 34 as the certain portion of an orbiting shaft, i.e. the Oldham's rings 35 is provided between the bearing support 27 and the orbiting plate 34, the Oldham's ring 35 does not be increased in the temperature even in the temperature raise of the orbiting scroll 33. Thus, longer life of the Oldham's ring 35 may be achieved. Less thermal expansion of the Oldham's ring 35 also provides its stable efficiency. Further, locating the Oldham's ring 35 in the lower portion of the casing 21 allows the Oldham's ring 35 to be readily lubricated, and thereby longer life and enhanced efficient of the Oldham's ring 35 may be achieved.

[0046]FIG. 3 is a schematic sectional view showing a scroll compressor according to the second embodiment of the present invention, which is used as a refrigerant gas compressor. As shown in FIG. 3, a chamber 52 is liquid-tightly fixed to the casing 51. A stationary scroll 53 is fixed to the chamber 52, and the stationary scroll 53 is provided with a spiral lap. A high-pressure chamber 54 is fixed to the stationary scroll 53, and a stator 55 is fixed to the casing 51. A rotary shaft 57 is rotatably supported by the casing 51 through ball bearings 58 and 59, and a rotor 56 is fixed to the rotary shaft 57. A motor comprises the stator 55, the rotor 56. Further, an orbiting shaft 60 is rotatably supported by the rotary shaft 57 through ball bearings 61 and 62. Respective axes of the rotary shaft 57 and the orbiting shaft 60 are eccentrically arranged each other. Specifically, the orbiting shaft 60 is eccentrically and rotatably supported by the rotary shaft 57. An orbiting scroll 63 is mounted to the upper portion of the orbiting shaft 60. A seal 64 is provided between the orbiting scroll 63 and the stationary scroll 53, and a balancer 65 is mounted to the lower portion of the orbiting scroll 63. The orbiting scroll 63 is provided with a lap formed in the same configuration as that of the stationary scroll 53. Respective laps of the orbiting scroll 63 and the stationary scroll 53 are overlappedly engaged with each other to form a plurality of compressing chambers. Further, an orbiting plate 66 is fixed to the lower portion of the orbiting shaft 60, i.e., in the downward section on the sheet of FIG. 3. An Oldham's ring 67 having protrusions 68 and 69 is provided between the casing 51 and the orbiting plate 64. A groove 70 is provided in the casing 51, and a slit 71 is provided in the orbiting plate 64. The groove 70 and the slit 71 are arranged in the directions orthogonal to each other (In FIG. 3, while the one of the groove 70 and the slit 71 should be illustrated, for simplifying the explanation, both of the groove 70 and the slit 71 are shown together.), and the protrusions 68 and 69 are engaged with the groove 70 and the slit 71. This construction including a part of the casing 51 and the Oldham's ring 65 provides the anti-self-rotation device which allows the orbiting shaft 60 to be eccentrically orbited and prevents the self-rotation of the orbiting shaft 60. Specifically, the portion of the casing 51 as the stationary portion of the anti-self-rotation device is fixed to the casing 51, and the Oldham's ring 65 as the movable portion of the anti-self-rotation device is engaged with the orbiting plate 66 as the certain portion of the orbiting shaft. Further, a lid 72 is mounted to the lower portion of the casing 51, i.e. the lower section on the sheet of FIG. 3. A suction pipe 77 is connected to the stationary scroll 53 so as to communicate with the chamber 52 and the compressing chambers of the compressor body. A discharge pipe 78 is connected with the high-pressure chamber 54 so as to communicate with the compressing chambers of the compressor body through a check valve 79. The eccentric-rotation driving unit comprises the casing 51, the motor, the rotary shaft 57, the orbiting shaft 60, and the anti-self-rotation device.

[0047] In this scroll compressor, when a winding of the stator 55 is energized, the rotor 56 and the rotary shaft 57 are rotated, and the orbiting shaft 60 is eccentrically orbited about the axis of the rotary shaft 57. However, the anti-self-rotation device comprising the Oldham's ring 65 prevents the self-rotation of the orbiting shaft 60. Thus, the orbiting shaft 60 and the orbiting scroll 63 are eccentrically orbited without any rotation to the casing 51 and the stationary scroll 53, and thereby the volume of the compression chambers formed between the orbiting scroll 63 and the stationary scroll 53 is gradually reduced. Then, a refrigerant gas is sucked from the suction pipe 77, and compressed in the compression chambers, whereafter the gas is discharged from the discharge pipe 78.

[0048]FIG. 4 is a schematic sectional view showing a scroll compressor according to the third embodiment of the present invention, and FIG. 5 is a sectional view taken along the line B-B of FIG. 4. As shown in these figure, a support member 81 is fixed to the casing 21, and a movable plate 82 is supported by the support member 81 so as to be movable in the longitudinal direction on the sheet of FIG. 5. The movable plate 82 is formed with a rectangular opening 83 having a longitudinal direction orthogonal to the moving direction of the movable plate 82. Notched surfaces 84 are provided on both sides of the lower portion of the orbiting shaft 30. The notched surfaces 84 are arranged in parallel with the axis of the orbiting shaft 30, and the notched surfaces 84 are also arranged in parallel with each other. The notched surfaces 84 are engaged with the peripheral surface of the opening 83 extending in the width direction of the opening 83. Specifically, this width direction of the opening 83 corresponds to a direction perpendicular to the longitudinal direction on the sheet of FIG. 5. This construction including the support member 81 and the movable plate 82 provides an anti-self-rotation device which allows the orbiting shaft 30 to be eccentrically orbited and prevents the self-rotation of the orbiting shaft 30. That is, the support member 81 as the stationary portion of the anti-self-rotation device is fixed to the casing 61, and the movable plate 82 as the movable portion of the anti-self-rotation device are engaged with the notched surfaces 84 as the certain portion of an orbiting shaft.

[0049] In this scroll compressor, when a winding of the stator 23 is energized, the rotor 24 and the rotary shaft 25 are rotated, and the orbiting shaft 30 is eccentrically orbited about the axis of the rotary shaft 25. However, the anti-self-rotation device comprising the support member 81 and the movable plate 82 prevents the self-rotation of the orbiting shaft 30. Thus, the orbiting shaft 30 and the orbiting scroll 33 are eccentrically orbited without any rotation to the casing 21 and the stationary scroll 22, and thereby the volume of the compression chambers formed between the orbiting scroll 33 and the stationary scroll 22 is gradually reduced. Then, a gas to be compressed is sucked from the suction pipe 40, and compressed in the compression chambers, whereafter the gas is discharged from the discharge pipe 41.

[0050] In this scroll compressor, since the support member 81 as the stationary portion of the anti-self-rotation device is fixed to the casing 21, and the movable plate 82 as the movable portion of the anti-self-rotation device is engaged with the notched surfaces 84 as a portion of the orbiting shaft, the movable plate 82 does not be increased in the temperature even in the temperature raise of the orbiting scroll 33. Thus, longer life of the movable plate 82 may be achieved. Less thermal expansion of the movable plate 82 also provides its stable efficiency. Further, locating the movable plate 82 in the lower portion of the casing 21 allows the movable plate 82 to be readily lubricated, and thereby longer life and enhanced efficient of the movable plate 82 may be achieved.

[0051] In the above embodiments, the orbiting plate 34, 66 is fixed at the lower portion of the orbiting shaft 30, 60. However, it should be understood that the orbiting plate may be fixed to any other portion of the orbiting shaft. When the orbiting plate, for example, is fixed to the upper potion of the orbiting shaft, an adverse effect of the torsion in the orbiting shaft may be reduced and thereby the efficiency of the compressor body may be enhanced. Further, while the notch surfaces 84 are provided in the lower portion of the orbiting shaft 30 in the above embodiments, the notch surfaces may be provided in any other portion of the orbiting shaft. When the notch surface, for example, is provided in the upper potion of the orbiting shaft, an adverse effect of the torsion in the orbiting shaft may be reduced and thereby the efficiency of the compressor body may be enhanced. When the orbiting shaft is inserted into the opening, the movable plate first is divided into two parts at the middle thereof and then jointed after the orbiting shaft is inserted into the opening. In addition, while the compressor body is provided to one side of the orbiting shaft 30, 60 in the above embodiments, the compressor body may be provided to both sides of the orbiting shaft.

[0052] As described above, the stationary portion of the anti-self-rotation device is fixed to the casing, and the movable portion of the anti-self-rotation device is engaged with the certain portion of the orbiting shaft, so that the anti-self-rotation device does not be increased in the temperature even in the temperature raise of the orbiting scroll. Thus, longer life of the anti-self-rotation device may be achieved. Further, less thermal expansion of the anti-self-rotation device may provide longer life and stable efficient of the anti-self-rotation device.

[0053]FIG. 7 is a schematic sectional view showing a scroll compressor according to the fourth embodiment of the present invention, and FIG. 8 is a sectional view taken along the line C-C of FIG. 7. As shown in these figures, a stationary scroll 122 is fixed to a casing or fixed body 121, and a spiral lap is provided in the stationary scroll 122. A stator 123 is fixed to the casing 121. Bearing supports 126 and 127 are also fixed to the casing 121, and a rotary shaft 125 is rotatably supported by the bearing supports 126 and 127 through bearings 128 and 129. A rotor 124 is fixed to the rotary shaft 125. A motor comprises the stator 123 and the rotor 124, and this motor serves as a driving device for rotatably driving the rotary shaft 125. A hollow orbiting shaft 130 is rotatably supported by the rotary shaft 125 through bearings 131 and 132, and respective axes of the rotary shaft 125 and the hollow orbiting shaft 130 are eccentrically arranged each other. Thus, the hollow orbiting shaft 130 is eccentrically and rotatably supported by the rotary shaft 125. A mounting member 133 is fixed within the hollow orbiting shaft 130, and an orbiting scroll 135 is mounted to the mounting portion 134 of the mounting member 133. The orbiting scroll 135 is provided with a lap formed in the same configuration as that of the stationary scroll 122. These laps of the orbiting scroll 135 and the stationary scroll 122 are overlappedly engaged with each other to form a plurality of compression chambers. A compressor body comprises the stationary scroll 122 and the orbiting scroll 135, and this compressor body is located inside the rotor 124 and the hollow orbiting shaft 130. A hollow orbiting plate 136 is fixed to the lower portion of the hollow orbiting shaft 130, i.e., the downward section on the sheet of FIG. 7, and an Oldham's ring 137 having protrusions 138 and 139 is provided between the bearing support 127 and the hollow orbiting plate 136. Grooves 140 and 141 orthogonal to each other are provided in the bearing support 127 and the hollow orbiting plate 136, respectively, and the protrusions 138 and 139 are engaged with the grooves 140 and 141. This construction including the Oldham's ring 137 provides an anti-self-rotation device which allows the hollow orbiting shaft 130 to be eccentrically orbited and prevents the self-rotation of the hollow orbiting shaft 130. Specifically, the anti-self-rotation device is provided between the hollow orbiting plate 136 and the casing 121. Further, a suction pipe 142 is connected to the stationary scroll 122, and a discharge pipe 143 is connected to the stationary scroll 122. Each of the suction pipe 142 and the discharge pipe 143 communicates with the compression chambers. The eccentric-rotation driving unit comprises the casing 121, the motor, the rotary shaft 125, the hollow orbiting shaft 130, and the anti-self-rotation device.

[0054] In this scroll compressor, when a winding of the stator 123 is energized, the rotor 124 and the rotary shaft 125 are rotated, and the hollow orbiting shaft 130 is eccentrically orbited about the axis of the rotary shaft 125. However, the anti-self-rotation device including the Oldham's ring 137 prevents the self-rotation of the orbiting shaft 130. Thus, the orbiting scroll 135 is orbited eccentrically to the casing 121 and the stationary scroll 122 without any self-rotation of the orbiting scroll 135 and thereby the volume of the compression chambers formed between the orbiting scroll 135 and the stationary scroll 122 is gradually reduced. Then, a gas to be compressed, such as refrigerant gas, is sucked from the suction pipe 142, and compressed in the compression chambers, whereafter the gas is discharged from the discharge pipe 143.

[0055] In this scroll compressor, the compressor body is located inside the rotor 124 and the hollow orbiting shaft 130 so that the dimension in the axial direction of the rotary shaft 125, i.e. in the longitudinal direction on the sheet of FIG. 7, may be reduced. Further, the hollow orbiting shaft 130 is not directly mounted to the compressor body and thereby a heat of the compressor body is hardly transmitted to the hollow orbiting shaft 130, so that the hollow orbiting shaft 130 is not deformed by such heat. Thus, each lap of the stationary scroll 122 and the orbiting scroll 135 may avoid conflicting with each other, and thereby the orbiting scroll 122 and the stationary scroll 135 may be prevented from being damaged. Furthermore, since the Oldham's ring 137 is provided between the bearing support 127 and the hollow orbiting plate 136, the Oldham's ring 137 does not be increased in the temperature even in the temperature raise of the orbiting scroll 135. Thus, longer life of the Oldham's ring 137 may be achieved. Less thermal expansion of the Oldham's ring 137 also provides its stable efficiency.

[0056]FIG. 9 is a schematic sectional view showing a scroll compressor according to the fifth embodiment of the present invention. As shown in FIG. 9, a stationary scroll 151 is fixed to the casing 121, and the stationary scroll 151 is provided with a spiral lap. An orbiting scroll 153 is mounted to the mounting portion 152 of the mounting member 133. The orbiting scroll 153 is provided with a lap formed in the same configuration as that of the stationary scroll 151. Respective laps of the orbiting scroll 153 and the stationary scroll 151 are overlappedly engaged with each other to form a plurality of compression chambers. A compressor body comprises the stationary scroll 151 and the orbiting scroll 153, and this compressor body is located inside the rotor 124 and the hollow orbiting shaft 130. Further, a suction pipe 154 is connected to the stationary scroll 151, and a discharge pipe 155 is connected to the stationary scroll 151. The suction pipe 154 and the discharge pipe 155 communicate with the compression chambers.

[0057] In this scroll compressor, a gas to be compressed is sucked from the suction pipe 142, and compressed in the compression chambers, whereafter the gas is discharged from the discharge pipe 143. Simultaneously, the gas to be compressed is sucked from the suction pipe 154, and compressed in the compressed chambers, whereafter the gas is discharged from the discharge pipe 155.

[0058] In this scroll compressor, the gas to be compressed may be compressed by two compressor bodies; one compressor body comprising the stationary scroll 122 and the orbiting scroll 135, and another compressor body comprising the stationary scroll 151 and the orbiting scroll 153. Thus, when these two compressor bodies are connected in parallel with each other, larger volume may be provided, and when they otherwise are connected in series with each other, higher compressibility may be provided. Further, the mounting portions 134 and 152 may be shortened, and thereby higher torsional rigidity of the mounting portions 134 and 152 and less buckling deformation may be achieved. This allows various compressor bodies to be mounted to the mounting portions 134 and 152. Thus, the scroll compressor may assure a substantially constant performance regardless of the temperature, and it may be used in either of the cold and hot areas in case of applied as a compressor for air conditioners.

[0059]FIG. 10 is a schematic sectional view showing a scroll compressor according to the sixth embodiment of the present invention, and FIG. 11 is a sectional view taken along the line D-D of FIG. 10. As shown in these figure, a stationary scroll being a part of a compressor body 162 is fixed to a casing 161. A stator 163 is fixed to the casing 161, and a bearing support 164 is fixed to the casing 161. A rotary shaft 166 is rotatably supported by a bearing support 164 through a bearing 165, and a rotor 168 is fixed to the rotary shaft 166 through a coupling disk 167. A motor comprises the stator 163 and the rotor 168. Further, an orbiting shaft 170 is rotatably supported by the rotary shaft 166 through a bearing 169. Respective axes of the rotary shaft 166 and the orbiting shaft 170 are eccentrically arranged each other. Thus, the orbiting shaft 170 is eccentrically and rotatably supported by the orbiting shaft 170. An orbiting scroll being a part of the compressor body 162 is mounted to the end portion of the orbiting shaft 170, and the compressor body 162 is located inside the rotor 168. A support member 171 is fixed to the casing 161. A movable plate 172 is supported by the support member 171 so as to be movable in the longitudinal direction on the sheet of FIG. 11. The movable plate 172 is formed with a rectangular opening 173 having a longitudinal direction orthogonal to the moving direction of the movable plate 172. Specifically, this longitudinal direction of the rectangular opening 173 corresponds to the lateral direction on the sheet of FIG. 11. Notched surfaces 174 are provided on both sides of the center portion of the orbiting shaft 170. The notched surfaces 174 are arranged in parallel with the axis of the orbiting shaft 170, and the notched surfaces 174 are also arranged in parallel with each other. The notched surfaces 174 are engaged with the peripheral surface of the opening 173 extending in the width direction of the opening 173. Specifically, this width direction of the opening 173 corresponds to a direction perpendicular to the longitudinal direction on the sheet of FIG. 11. This construction including the support member 171 and the movable plate 172 provides an anti-self-rotation device which allows the orbiting shaft 170 to be eccentrically orbited and prevents the self-rotation of the orbiting shaft 170. That is, the support member 171 as the stationary portion of the anti-self-rotation device is fixed to the casing 161, and the movable plate 172 as the movable portion of the anti-self-rotation device are engaged with the notched surfaces 174 as a portion of the orbiting shaft. The eccentric-rotation driving unit comprises the casing 161, the motor, the rotary shaft 166, the orbiting shaft 170, and the anti-self-rotation device.

[0060] In this scroll compressor, when a winding of the stator 163 is energized, the rotor 168 and the rotary shaft 166 are rotated, and the orbiting shaft 170 is eccentrically orbited about the axis of the rotary shaft 166. However, the anti-self-rotation device comprising the support member 171 and the movable plate 172 prevents the self-rotation of the orbiting shaft 170. Thus, the orbiting shaft 170 and the orbiting scroll are eccentrically orbited without any rotation to the casing 161 and the stationary scroll, and thereby the volume of the compression chambers formed between the orbiting scroll and the stationary scroll is gradually reduced.

[0061] In this scroll compressor, the compressor body 162 is located inside the rotor 168 so that the dimension in the axial direction of the rotary shaft 166, i.e. in the longitudinal direction on the sheet of FIG. 10, may be shorten. Further, the diameter of the orbiting shaft 170 may be increased without increasing the outside dimension of the scroll compressor unit, and thereby higher rigidity of the orbiting shaft 170 and less deformation of the orbiting shaft 170 may be achieved. Thus, each lap of the orbiting scroll and stationary scroll in the compressor body 162 may avoid conflicting with each other, and thereby the orbiting scroll and stationary scroll in the compressor body 162 may be prevented from being damaged. Further, since the anti-self-rotation device is obtained only by providing the opening 173 in the movable plate 172 and providing the notched surfaces 174 in both sides of the bottom of the orbiting shaft 170, simpler structure and lower manufacturing cost may be achieved.

[0062] In the above embodiments, the motor including the stator 123 and the rotor 124 is used as a driving device for rotatably driving the rotary shaft 125. However, it should be understood that a belt-type driving device may be applied as the driving device for rotatably driving the rotary shaft. Further, while the hollow orbiting plate 136 is fixed at the lower portion of the hollow orbiting shaft 130 in the above embodiments, the hollow orbiting plate 136 may be fixed to any other portion of the hollow orbiting shaft 130. Furthermore, while the coupling disk 167 is used as a coupling member in the above embodiments, a plurality of coupling rods may be applied as coupling members. In addition, in the above embodiments, the orbiting scrolls 135 and 153 are mounted to the mounting member 133. However, the orbiting scroll may be mounted directly to the hollow orbiting shaft. When the compressor body is cooled by supplying wind to the center thereof, for example, the compressor body 162 is cooled by supplying wind to the center thereof through the inner passage provided in the orbiting shaft 170, the thermal deformation of the compressor body may be reduced. Thus, the interference between respective laps of the orbiting scroll and stationary scroll in the compressor body and resulting damage of the laps of the orbiting scroll and the stationary scroll in the compressor body may further be prevented.

[0063] As described above, in the scroll compressor according to the present invention, locating the compressor body inside the orbiting shaft allows the dimension in the axial direction of the rotary shaft to be effectively shortened. Further, locating the compressor body inside the rotor allows the dimension in the axial direction of the rotary shaft to be shortened.

[0064]FIG. 12 is a sectional view showing an overall structure of one example of a scroll-type pressure transformer according to the present invention, and FIGS. 13 and 14 are exploded views thereof. This scroll-type pressure transformer comprises a driving unit, a scroll device and a casing to couple them.

[0065] The driving unit comprises a motor 301, an orbiting shaft 303 located in a rotary shaft 302 of the motor 301, an anti-self-rotation mechanism 304 of the orbiting shaft 303, and a casing 306 for fixing the motor 301. The motor 301 comprises a stator 301 a fixed to the casing 306, a rotary shaft 302 rotatable in a space of the stator 301 a and having an eccentric axial hollow portion therein, and a rotor 301 b fixed to the rotary shaft 302 and facing to the stator 301 a with a small gap therebetween. Bearings 302 a and 302 b are provided on both ends of the hollow portion within the rotary shaft 302, and the orbiting shaft 303 is relatively rotatably supported through the bearings 302 a and 302 b. The shaft center of the orbiting shaft 303 is arranged eccentrically to the shaft center of the rotary shaft 302. Thus, when the rotary shaft 302 is rotated, the orbiting shaft 303 is orbited along the circumference having a radius R corresponding to the distance R between the both shaft centers.

[0066] The anti-self-rotation mechanism 304 according to the present invention includes an Oldham's ring 444 having a pair of first protrusions 441, 441 provided along a diagonal line on one side of the Oldham's ring 444 and a pair of second protrusions 442, 442 provided along a diagonal line orthogonal to the above diagonal line on the other side of the Oldham's ring 444. An orbiting plate 446 fixed to the orbiting shaft 303 has, on the inner surface thereof, a pair of radial grooves (not shown) which allows the first protrusions 441 of the Oldham's ring 444 to be moved therein. The outer surface of the casing 306 is formed with a pair of radial grooves 448 which allows the second protrusions 442 of the Oldham's ring 444 to be moved therein. The Oldham's ring 444 is restrained by the radial grooves (not shown) of the orbiting plate 446 and the radial grooves 448 of the casing 306 so that the orbiting shaft 303 may be orbited without its self-rotation.

[0067] Among a pair of stationary scroll members 340 and 342 each having a scroll, a protrusion 345 of a stationary scroll member 342 located on the side of the motor is formed with an opening 347 a having a bearing 345 a coaxial with the rotary shaft 302 to rotatably bear the rotary shaft 302, and a through hole 347 b coaxial with the rotary shaft 302 and having an inner diameter slightly larger than the orbiting diameter of the orbiting shaft 303. The protrusion 345 of the stationary scroll member 342 is fixed to the casing 306 of the motor 301 by a screw or the like. The other stationary scroll member 340 includes, on the inner surface thereof, a scroll 340 a having the same configuration as that of the scroll 342 a of the stationary scroll member 342. The stationary scroll member 340 also has a recessed portion 340 b rotatably bearing the top portion of the orbiting shaft 303 at a position corresponding to a through hole 344 a of an orbiting scroll member 344.

[0068] The orbiting scroll member 344 has spiral scrolls 349 a and 349 b on both sides thereof, and a sleeve 344 b at its approximate center thereof. The sleeve 344 b is fastened to the orbiting shaft 303 by a screw, lock or the like. Thus, when both stationary scroll members 340 and 342 are coupled through the orbiting scroll member 344 with a screw or the like, the scroll spaces are formed on both sides of the orbiting scroll member 344. These scroll spaces are moved toward the side of the orbiting shaft 303 (i.e. the center side of the compressor) as they are gradually reduced in volume by the orbiting of the orbiting scrolls 349 a and 349 b. Each scroll space has a low-pressure area in the outward portion thereof and has a high-pressure area at the center portion thereof. Since the configuration and operation of the scroll are known, their description will be omitted. A through hole 344 d is formed in a disk-shaped base plate 344 c of the orbiting scroll member 344 in the high-pressure area to communicate the scroll spaces on both sides respectively. A vent passage communicating with the low-pressure area of the scroll spaces operates as an inlet port 320, and a vent passage communicating with the high-pressure area of the scroll spaces operates as a discharge port 322.

[0069] The scroll-type pressure transformer shown in FIGS. 12 to 14 may function as a scroll vacuum pump.

[0070]FIG. 15 is a sectional view showing an overall structure of another example of a scroll-type pressure transformer according to the present invention having scroll spaces on both sides thereof, wherein the orbiting scroll member 344 fastened to the orbiting shaft 303 is slidably in the axial direction. In FIG. 15, the same elements as those of the scroll-type pressure transformer in FIGS. 12 to 14 are defined by the same reference numbers.

[0071] Generally, the pressure transformer, for example, is operated under an adequate difference in gas pressure by arranging a gas pressure in the upper scroll space higher than a gas pressure in the lower scroll space. However, under various operation conditions and the conditions of each portion of the orbiting scroll member 344, such as temperature rise, and deformation by vibration, an excessive thrust force may load to the bearing 302 b of the orbiting shaft 303. To cope with these undesirable condition, as shown in FIG. 15, the orbiting scroll member 344 is engaged with the orbiting shaft 303 slidably in the axial direction by, for example, key or P-profile and fastened by a spring 350 and a screw 351 thereto. By virtue of this structure, the above excessive thrust force is absorbed by the spring 350 so that the thrust force on the bearing 302 b of the orbiting shaft 303 may be reduced. Thus, the bearing of the orbiting scroll member is not required to have an excessively high strength and thereby its cost may be reduced.

[0072] The embodiment of the present invention has been described with reference to the drawings of the particular embodiment. However, the present invention is not limited to those and various modifications may be made. For example, the anti-self-rotation mechanism is not limited to the Oldham's ring and a crankshaft type anti-self-rotation mechanism as shown in FIG. 18 may be applied. Further, the anti-self-rotation mechanism is not essentially required to mount to the orbiting shaft in the position outside the motor farthest from the scroll as shown in FIGS. 12 and 13, and it may be provided outside the scroll as shown in FIG. 15, or halfway between the motor and the scroll. Further, in the motor as shown in figures, the orbiting shaft is not essentially required to penetrate the rotary shaft, and a commercially available motor, for example, may be applied and an orbiting shaft may be rotatably mounted within the hollow portion of the rotary shaft coupled to the rotary shaft of the motor.

[0073] As described above, in the scroll-type pressure transformer according to the present invention, the orbiting scroll member is directly fastened or fastened slidably to the orbiting shaft which is orbited without any self-rotation by the anti-self-rotation mechanism provided between the orbiting plate mounted to the orbiting shaft and the casing. Thus, the overall device may be simplified in structure, and its cost may be reduced. Further, the complicated mechanism is not required for the anti-self-rotation mechanism of the orbiting shaft, and the deformation of the orbiting scroll member due to the thermal expansion or the vibration may be reduced. Thus, the orbiting scroll member may be orbited precisely, and the durability and quietness of the device may be enhanced. 

We claim:
 1. A scroll compressor comprises; a casing; a stationary scroll fixed to said casing; a stator fixed to said casing; a rotary shaft rotatably supported by said casing; a rotor fixed to said rotary shaft; an orbiting shaft eccentrically and rotatably supported by said rotary shaft; an orbiting scroll fixed to said orbiting shaft, and an anti-self-rotation device having a stationary portion fixed to said casing and a movable portion engaged with said orbiting shaft.
 2. A scroll compressor comprising: a fixed body; a stationary scroll fixed to said fixed body, said stationary scroll being a part of a compressor body; a rotary shaft rotatably supported by said fixed body; a driving device for rotatably driving said rotary shaft; a hollow orbiting shaft eccentrically and rotatably supported by said rotary shaft; an anti-self-rotation device for preventing the self-rotation of said hollow orbiting shaft; and an orbiting scroll fixed to said hollow orbiting shaft, said orbiting scroll being a part of said compressor body, wherein said compressor body is located inside said hollow orbiting shaft.
 3. A scroll compressor comprises: a casing; a stationary scroll fixed to said casing, said stationary scroll being a part of a compressor body; a stator fixed to said casing; a rotary shaft rotatably supported by said casing; a rotor fixed to said rotary shaft; an orbiting shaft eccentrically and rotatably supported by said rotary shaft; an anti-self-rotation device for preventing the self-rotation of said orbiting shaft; and an orbiting scroll fixed to said orbiting shaft, said orbiting scroll being a part of said compressor body, wherein said compressor body is located inside said rotor.
 4. A scroll compressor as defined in claim 3 , wherein said orbiting shaft is a hollow orbiting shaft, wherein said orbiting scroll is mounted on a mounting member fixed within said hollow orbiting shaft.
 5. A scroll compressor as defined in claim 3 , wherein said rotor is fixed to said rotary shaft through a coupling member.
 6. A scroll-type pressure transformer comprising; a casing; a motor supported by said casing through a first bearing and provided with a rotary shaft having an eccentric hollow portion; an orbiting shaft penetrating said hollow portion of said rotary shaft and rotatably supported by said rotary shaft through a second bearing; an orbiting scroll member fastened to said orbiting shaft and having scrolls on both sides of said orbiting scroll member; a pair of stationary scroll members fixed to said casing and opposed to each scroll of said orbiting scroll member; an anti-self-rotation device provided in said orbiting shaft; a gas inlet port communicating with a low-pressure area of a pair of scroll spaces formed between said orbiting scroll member and said stationary scroll members on both sides of said orbiting scroll member, and a gas discharge port communicating with a high-pressure area of said scroll spaces.
 7. A scroll-type pressure transformer as defined in claim 6 , wherein said anti-self-rotation device is provided between said orbiting plate fixed to said orbiting shaft and said casing.
 8. A scroll-type pressure transformer as defined in claim 6 or 7 , wherein said orbiting scroll member is fastened to said orbiting shaft slidably in the axial direction of said orbiting shaft. 